WO 03/055207 describes that time sharing an analog-to-digital converter for multiple input signals is a well-known way to reduce the number of analog-to-digital converters in a video and/or audio system. One technique for sharing an analog-to-digital converter in such systems involves multiplexing. A multiplexer simultaneously receives analog U and V input signals, and is switched in dependence upon an enable signal to output selected ones of the received analog U and V signals in an alternating manner. An analog-to-digital converter receives the analog U and V output signals from the multiplexer and digitizes the received U and V signals in dependence upon a clock signal, wherein each interval of the clock signal defines a single clock cycle or time interval. The frequency of the clock signal may be two times the frequency of the enable signal. A demultiplexer receives the digital U and V signals from the analog-to-digital converter, and is switched in dependence upon the enable signal two output the digital U and V signals.